title: Magneto-dielectric effects induced by optically-generated intermolecular charge-transfer states in organic semiconducting materials.
abstract: Traditionally, magneto-dielectric effects have been developed by combining ferroelectric and magnetic materials. Here, we show a magneto-dielectric effect from optically-generated intermolecular charge-transfer states in an organic semiconducting donor:acceptor (PVK:TCNB) system. We observe in magnetic field effects of photoluminescence that a magnetic field can change singlet/triplet population ratio in intermolecular charge-transfer states. Furthermore, our theoretical analysis and experimental evidence indicate that the singlets and triplets in charge-transfer states have stronger and weaker electrical polarizations, respectively. Therefore, the observed magneto-dielectric effect can be attributed to magnetically-dependent singlet/triplet ratio in intermolecular charge-transfer states. In principle, a magneto-dielectric effect can be generated through two different channels based on magneto-polarization and magneto-current effects when the singlet/triplet ratio in intermolecular charge-transfer states is changed by a magnetic field. We find, from the simulation of dielectric effects, that magneto-polarization and magneto-current effects play primary and secondary roles in the generation of magneto-dielectric effect.
authors.affiliation: Department of Materials Science and Engineering, University of Tennessee - Knoxville Tennessee 37996, USA.
authors.forename: Huidong
authors.initials: H
authors.lastname: Zang
authors.forename: Liang
authors.initials: L
authors.lastname: Yan
authors.forename: Mingxing
authors.initials: M
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: He
authors.forename: Zheng
authors.initials: Z
authors.lastname: Gai
authors.forename: Ilia
authors.initials: I
authors.lastname: Ivanov
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Long
authors.initials: L
authors.lastname: Chiang
authors.forename: Augustine
authors.initials: A
authors.lastname: Urbas
authors.forename: Bin
authors.initials: B
authors.lastname: Hu